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Xiangwei Zhou

Bio: Xiangwei Zhou is an academic researcher from Louisiana State University. The author has contributed to research in topics: Cognitive radio & Spectral efficiency. The author has an hindex of 22, co-authored 93 publications receiving 1836 citations. Previous affiliations of Xiangwei Zhou include Zhejiang University & Southern Illinois University Carbondale.


Papers
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Journal ArticleDOI
TL;DR: An overview of recent research achievements of including spectrum sensing, sharing techniques and the applications of CR systems is provided.
Abstract: Cognitive radio (CR) can successfully deal with the growing demand and scarcity of the wireless spectrum. To exploit limited spectrum efficiently, CR technology allows unlicensed users to access licensed spectrum bands. Since licensed users have priorities to use the bands, the unlicensed users need to continuously monitor the licensed users' activities to avoid interference and collisions. How to obtain reliable results of the licensed users' activities is the main task for spectrum sensing. Based on the sensing results, the unlicensed users should adapt their transmit powers and access strategies to protect the licensed communications. The requirement naturally presents challenges to the implementation of CR. In this article, we provide an overview of recent research achievements of including spectrum sensing, sharing techniques and the applications of CR systems.

259 citations

Journal ArticleDOI
TL;DR: An optimal approach based on the dual method and a suboptimal approach are developed to reduce complexity while maintaining reasonable performance in cognitive radio (CR) systems.
Abstract: In this paper, we investigate joint relay selection and power allocation to maximize system throughput with limited interference to licensed (primary) users in cognitive radio (CR) systems. As these two problems are coupled together, we first develop an optimal approach based on the dual method and then propose a suboptimal approach to reduce complexity while maintaining reasonable performance. From our simulation results, the proposed approaches can increase the system throughput by over 50%.

228 citations

Journal ArticleDOI
TL;DR: A comprehensive survey on the history and applications of Faster-than-Nyquist (FTN) signaling and the basic principles and the system framework of FTN signaling are presented.
Abstract: Faster-than-Nyquist (FTN) signaling can improve the bandwidth utilization. In this paper, we will provide a comprehensive survey on the topic. The history and the applications of FTN signaling are first introduced. Then, the basic principles and the system framework of FTN signaling are presented. Next, more details on transmitter and receiver optimization are discussed. Finally, the current research challenges on FTN signaling are identified and conclusions are provided.

118 citations

Proceedings ArticleDOI
09 Jan 2010
TL;DR: This paper investigates how a CR user senses multiple channels and determine the optimal transmission duration and power allocation and finds a closed-form solution for transmission duration for chosen channels.
Abstract: Cognitive radio (CR) networks are designed to utilize the licensed spectrum when it is not llsed by the primary (licensed) users. In this paper, we investigate how a CR user senses multiple channels and determine the optimal transmission duration and power allocation. When performing optimization, we take energy efficiency, throughput, and interference with the primary users into consideration and find a closed-form solution for transmission duration for chosen channels. It is shown that the proposed optimization approach significantly improves energy efficiency and throughput of CR networks.

81 citations

Proceedings ArticleDOI
08 Dec 2008
TL;DR: In this paper, detection timing and channel selection for periodic spectrum sensing are investigated to improve the performance of cognitive radio (CR) users under a given level of interference with licensed users, the detection timing scheme utilizes the statistics of the licensed channel occupancy to determine the optimal starting point of each sensing action.
Abstract: In this paper, detection timing and channel selection for periodic spectrum sensing are investigated to improve the performance of cognitive radio (CR) users. Designed to maximize the channel efficiency of CR users under a given level of interference with licensed users, the detection timing scheme utilizes the statistics of the licensed channel occupancy to determine the optimal starting point of each sensing action. A channel selection scheme in the multichannel multiuser environment is also proposed to specify which channel to detect for the upcoming sensing action based on detection timing. Numerical results demonstrate that our schemes considerably improve the overall channel efficiency while protecting the communication among licensed users.

80 citations


Cited by
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01 Jan 2016
TL;DR: The table of integrals series and products is universally compatible with any devices to read and is available in the book collection an online access to it is set as public so you can get it instantly.
Abstract: Thank you very much for downloading table of integrals series and products. Maybe you have knowledge that, people have look hundreds times for their chosen books like this table of integrals series and products, but end up in harmful downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they cope with some harmful virus inside their laptop. table of integrals series and products is available in our book collection an online access to it is set as public so you can get it instantly. Our book servers saves in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Merely said, the table of integrals series and products is universally compatible with any devices to read.

4,085 citations

Journal ArticleDOI
TL;DR: The state-of-the-art survey of cooperative sensing is provided to address the issues of cooperation method, cooperative gain, and cooperation overhead.

1,800 citations

01 Jan 2007
TL;DR: In this paper, the authors provide updates to IEEE 802.16's MIB for the MAC, PHY and asso-ciated management procedures in order to accommodate recent extensions to the standard.
Abstract: This document provides updates to IEEE Std 802.16's MIB for the MAC, PHY and asso- ciated management procedures in order to accommodate recent extensions to the standard.

1,481 citations

Journal ArticleDOI
TL;DR: This paper provides a systematic overview on CR networking and communications by looking at the key functions of the physical, medium access control (MAC), and network layers involved in a CR design and how these layers are crossly related.
Abstract: Cognitive radio (CR) is the enabling technology for supporting dynamic spectrum access: the policy that addresses the spectrum scarcity problem that is encountered in many countries. Thus, CR is widely regarded as one of the most promising technologies for future wireless communications. To make radios and wireless networks truly cognitive, however, is by no means a simple task, and it requires collaborative effort from various research communities, including communications theory, networking engineering, signal processing, game theory, software-hardware joint design, and reconfigurable antenna and radio-frequency design. In this paper, we provide a systematic overview on CR networking and communications by looking at the key functions of the physical (PHY), medium access control (MAC), and network layers involved in a CR design and how these layers are crossly related. In particular, for the PHY layer, we will address signal processing techniques for spectrum sensing, cooperative spectrum sensing, and transceiver design for cognitive spectrum access. For the MAC layer, we review sensing scheduling schemes, sensing-access tradeoff design, spectrum-aware access MAC, and CR MAC protocols. In the network layer, cognitive radio network (CRN) tomography, spectrum-aware routing, and quality-of-service (QoS) control will be addressed. Emerging CRNs that are actively developed by various standardization committees and spectrum-sharing economics will also be reviewed. Finally, we point out several open questions and challenges that are related to the CRN design.

980 citations

Journal ArticleDOI
TL;DR: This paper bridges the gap between deep learning and mobile and wireless networking research, by presenting a comprehensive survey of the crossovers between the two areas, and provides an encyclopedic review of mobile and Wireless networking research based on deep learning, which is categorize by different domains.
Abstract: The rapid uptake of mobile devices and the rising popularity of mobile applications and services pose unprecedented demands on mobile and wireless networking infrastructure. Upcoming 5G systems are evolving to support exploding mobile traffic volumes, real-time extraction of fine-grained analytics, and agile management of network resources, so as to maximize user experience. Fulfilling these tasks is challenging, as mobile environments are increasingly complex, heterogeneous, and evolving. One potential solution is to resort to advanced machine learning techniques, in order to help manage the rise in data volumes and algorithm-driven applications. The recent success of deep learning underpins new and powerful tools that tackle problems in this space. In this paper, we bridge the gap between deep learning and mobile and wireless networking research, by presenting a comprehensive survey of the crossovers between the two areas. We first briefly introduce essential background and state-of-the-art in deep learning techniques with potential applications to networking. We then discuss several techniques and platforms that facilitate the efficient deployment of deep learning onto mobile systems. Subsequently, we provide an encyclopedic review of mobile and wireless networking research based on deep learning, which we categorize by different domains. Drawing from our experience, we discuss how to tailor deep learning to mobile environments. We complete this survey by pinpointing current challenges and open future directions for research.

975 citations